Can somebody me with my hw it’s due

Will have the greatest effect on human health. pollution in the a. troposphere b. stratosphere mesosphere d. thermosphere

The rise of advertising in the 1920s. i am good with seeing how advertisements shape the roaring twenties and how it developed a new way of life through modern days. but i am not sure what the details of advertising in the 1920s were. if possible can you send me links (preferrably credential links) to sources that maybe show like the first company to start advertising through the radio, how advertising benefits (statistics graphs), etc.

Which country was the last to join the allied powers? o great britain o france o united states o china